Question about Cars & Trucks
94 pontiac transport 3.8 v6.. engine miss from idle to upper rpms. tested injectors, voltage and ohms ok, tested coils ..ok ( they really are shocking), Cyl 5 seems to be dead(most of the time) swapped injector with a good one, NO CHANGE.. new ECM.. NO CHANGE, new plugs and wires..NO CHANGE... Help im pulling my hair out and I dont have alot left to pull on
Have a compression test done on the engine. Check for burnt valve or bent valve on that cylinder.
Posted on Apr 28, 2013
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Posted on Jan 02, 2017
SOURCE: dead cylinders 2003 sebring
it sounds like you may have the wires on the wrong coil. It should be #1 on the #4 coil, and the #3 wire on the #2 coil. you probably have them backwards so 1 and 3 are firing on the exhaust stroke.
the firing order is 1-3-4-2.
they should be hooked like this.
Posted on Jan 24, 2009
SOURCE: I am getting a misfire
Here is a copy of the "Policy Adjustment" that I took to the dealer with me this morning. Hope this helps any of you.
Subject: Special Policy Adjustment - Catalytic Converter #05551 -(09/14/2005)
Models: 2001-02 CHEVROLET IMPALA, MONTE CARLO
2001-02 PONTIAC GRAND PRIX
2001-02 BUICK REGAL
EQUIPPED WITH 3.4L (RPO LA1 - VIN E) OR 3.8L (RPO L36 - VIN K) V6 ENGINE
Some customers of 2001-02 Chevrolet Impala, Monte Carlo; Pontiac Grand Prix; and Buick Regal model vehicles, equipped with a 3.4L (RPO LA1 - VIN E) or 3.8L (RPO L36 - VIN K) V6 engine, may experience a condition where the vehicle exhaust catalytic converter is replaced due to complaints of lack of power or illumination of the Malfunction Indicator Lamp (MIL). This may be due to the front endcone insulation from the catalytic converter breaking away and blocking the front of the first catalyst brick and preventing the free flow of exhaust gas through the converter.
Special Policy Adjustment
This special policy covers the condition described above for a period of 10 years or 120,000 miles (190,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. The repairs will be made at no charge to the customer.
For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after September 15, 2005 are covered by this special policy and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to September 15, 2005 must be submitted to the Service Contract provider.
Involved are all 2001-02 Chevrolet Impala, Monte Carlo; Pontiac Grand Prix; Buick Regal model vehicles, equipped with a 3.4L (RPO LA1 - VIN E) or 3.8L (RPO L36 - VIN K) V6 engine and built within the following VIN breakpoints:
Parts required to complete this special policy are to be obtained from General Motors Service Parts Operations (GMSPO).
Converter, Catalytic (L36 engine)
Converter, Catalytic (LA1 engine)
Gasket, Catalytic Converter (Converter to I-Pipe, both)
Gasket, Exh Manif Pipe (L36)
Gasket, Exh Manif Pip (LA1)
General Motors will notify customers of this special policy on their vehicles (see copy of typical customer letter included with this bulletin - actual divisional letter may vary slightly).
Catalytic Converter Inspection
Begin the inspection by reviewing the condition described by the customer. Refer to "Description and Operation," SI document 657895, to help you determine the correct symptom diagnostic procedure when a malfunction exists.
Posted on Feb 08, 2009
SOURCE: 1999 Grand Am 3400 v6 misfire.
I was asking about the pushrods because I had this problem with one of these engines that had a bent push-rod. I robbed a push-rod out of an older 3100 and it was just a fraction of an inch longer which bottomed out the lifter. I figured it out by removing the valve cover and loosing the rockers when it was running and it smoothed out. I'm guessing you checked for vacuum leaks already. How about injection pulse on the number 6 cylinder when running. Another thing you could check is running compression. You said you checked compression but did you just check cranking compression or did you check running compression too.
Posted on Apr 09, 2010
Tips for a great answer:
Refer to Intermittent Conditions before starting.
Search for bulletins.
Observe the owners driving habits.
Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
Test for low fuel pressure. Refer to Fuel System Diagnosis .
Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
Inspect for fuel in the pressure regulator vacuum hose.
Ensure each injector harness is connected to the correct injector/cylinder.
Inspect for any items which may cause an engine to run rich, long term fuel trim is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 .
Inspect for any items which may cause an engine to run lean, long term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .
Test for conditions which cause an incorrect idle speed.
Throttle body tampering, excessive deposits, or damage--Refer to Fuel System Description .
Restricted air intake system
Large vacuum leak
Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
Inspect crankcase ventilation valve for proper operation.
Inspect the throttle position (TP) sensor and related wiring. Refer to DTC P0123 .
Monitor the 24X crank sensor and the CMP sensor signal present parameters on the scan tool. If both are not responding, test the sensor feed circuit. Both sensors use a separate feed circuit but are internally connected to power. Test all CKP sensor A and CMP sensor circuits for intermittents. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Monitor the 3X parameter on the scan tool. If the 3X is not responding, inspect the CKP sensor B and circuits for intermittents. Inspect the ignition control (IC) circuit, IC timing control circuit, low resolution engine speed signal circuit and the low reference circuit for intermittents. If these circuits become open, or shorted, they may not set a diagnostic trouble code (DTC) immediately, but are capable of causing driveability complaints. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test the exhaust gas recirculation (EGR) system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description .
Inspect the Transaxle Range Switch input with the vehicle in drive and the gear selector in drive or overdrive
Inspect for proper ignition voltage output using the following steps:
Attach the J 26792 Spark Tester to engine ground.
Connect the spark plug end of the spark plug wire to the J 26792 . Leave the other end of the spark plug wire connected to the coil being tested.
Connect the spark plug end of the companion spark plug wire to ground. The companion spark plug wire is the wire attached to the corresponding coil tower.
Crank the engine while observing the J 26792 . A spark should be observed.
Repeat the above steps for each coil.
If spark is not present at the coils, inspect for the following conditions:
Coils--Cracks, carbon tracking/arcing, or a resistance value outside the specified range
5000-8000 ohms (5K-8K ohms)
Spark plug wires--Signs of arcing, cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range
Spark Plug Wire Resistance
9 686 ohms per meter (3,000 ohms per foot)
Important: : Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.
Defective ignition module
Ignition system wiring--Loose ignition module feed or ground connection, or damaged system wiring
Remove spark plugs and inspect for the following conditions:
Burned or damaged electrodes
Improper heat range or reach
If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs. Refer to Spark Plug Inspection .
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